Hard to advise without critical details and specific samples with EXIF details.
The reason why people ask for EXIF a lot of times is because authors too often miss out critical details, whereas it's all contained in the EXIF.
Having said that, as for achieving DEEP (NOT shallow) DOF, using smaller apertures is one approach (with the necessary increase in ISO or amount of light or much longer shutter speeds, as appropriate).
When a smaller aperture is used effectively with hyperfocal practice, it may sometimes help, or not. All depends on specific situations/subject/set-up etc etc etc
Where critical quality and DOF control is required without worrying about diffraction degradation setting in, or when stopping down to the maximum is still not enough, one of the preferred approaches is to make use of the Scheimpflug principle (
http://en.wikipedia.org/wiki/Scheimpflug_principle) via tilt/shift lenses or a large format camera. Applying the Scheimpflug principle in real life is actually easier than reading the wiki entry, but mastering it with critical control can be quite challenging.
There is another technique that can be used. Does anyone know what it might be?
As regards your second question, we must find out WHY your photos was blur. Adding a flash blindly may or may not help, but we won't be helping you much because whatever is said would be pure speculative hamtam bola tikam tikam in the dark.
